The invention relates generally to thermal printers, and in particular to one in which a mismatch involving the availability of a dye donor supply and a dye receiver supply can be determinedxe2x80x94in which case the printing operation should be suspended and the short supply replenished to establish a match.
A typical dye donor web that is used in a thermal printer includes a repeating series of three different primary color sections or patches such as a yellow color patch, a magenta color patch and a cyan color patch. Also, there may be a transparent colorless laminating section or patch after the cyan color patch.
To make a color image print using a thermal printer, respective color dyes in a single series of yellow, magenta and cyan color patches on a dye donor web are successively heat-transferred, one over the other, onto a dye receiver sheet. Then, optionally, a transparent laminating material on a laminating patch of the web is heat-transferred onto the color image print. The dye transfer from each color patch to the dye receiver sheet is done one line of pixels at a time via a bead of selectively used heating or resistor elements on a thermal print head.
One example of a color image print-making process using a thermal printer is as follows.
1. A dye donor web and a dye receiver sheet are advanced forward in unison, with a yellow color patch of the donor web moving in contact with the receiver sheet longitudinally over a stationary bead of heating elements in order to effect a line-by-line yellow dye transfer from the yellow color patch to the receiver sheet. A web take-up spool draws the dye donor web forward over the bead of heating elements, and a pair of pinch and drive rollers draw the dye receiver sheet forward over the bead of heating elements. A platen roller holds the dye receiver sheet in a dye receiving relation with the dye donor web at the bead of heating elements.
2. Once the yellow dye transfer is completed, the platen roller is retracted from adjacent the print head to allow the pair of pinch and drive rollers to return the dye receiver sheet rearward in preparation for a second pass over the bead of heating elements.
3. Then, the platen roller is returned to adjacent the print head, and the dye donor web and the dye receiver sheet arc advanced forward in unison, with a magenta color patch of the donor web moving in contact with the receiver sheet longitudinally over the bead of heating elements in order to effect a line-by-line magenta dye transfer from the magenta color patch to the receiver sheet. The magenta dye transfer to the dye receiver sheet is in the same area on the receiver sheet as was subjected to the yellow dye transfer.
4. Once the magenta dye transfer is completed, the platen roller is retracted from adjacent the print head to allow the pair of pinch and drive rollers to return the dye receiver sheet rearward in preparation for a third pass over the bead of heating elements.
5. Then, the platen roller is returned to adjacent the print head, and the dye donor web and the dye receiver sheet are advanced forward in unison, with a cyan color patch of the donor web moving in contact with the receiver sheet longitudinally over the bead of heating elements in order to effect a line-by-line cyan dye transfer from the cyan color patch to the receiver sheet. The cyan dye transfer to the dye receiver sheet is in the same area on the receiver sheet as was subjected to the yellow and magenta dye transfers.
6. Once the cyan dye transfer is completed, the platen roller is retracted from adjacent the print head to allow the pair of pinch and drive rollers to return the dye receiver sheet rearward in preparation for a fourth pass over the bead of heating elements.
7. Then, the platen roller is returned to adjacent the print head, and the dye donor web and the dye receiver sheet are advanced forward in unison, with a transparent colorless laminating patch of the donor web moving in contact with the receiver sheet longitudinally over the bead of heating elements in order to effect a line-by-line laminating material transfer from the laminating patch to the receiver sheet. The laminating material is applied to the dye receiver sheet on top of the yellow, magenta and cyan dye transfers to that sheet.
8. Once the laminating material transfer is completed, the platen roller is retracted from adjacent the print head to allow the laminated dye receiver sheet to be returned rearward in preparation for exiting the printer.
9. Finally, the pair of pinch and drive rollers advance the laminated dye receiver sheet forward to an exit tray.
Instead of a dye receiver sheet, the print-making process can involve a dye receiver roll. In this case, each sheet must be cut from the roll.
According to one aspect of the invention, a method for determining a mismatch involving the availability of a dye donor supply and a dye receiver supply in a thermal printer when a particular print size and print quantity are selected, comprises:
comparing a remaining number of similar-size donor patches available on the dye donor supply with a remaining number of like-size donor patches required for the selected print size and print quantity, and should the former number be less than the latter number providing a warning; and
comparing a remaining length of dye receiver available on the dye receiver supply with a remaining length of dye receiver required for the selected print size and print quantity, and should the former length be less than the latter length providing a warning.
According to another aspect of the invention, apparatus is provided for performing the foregoing method.